The increasing globalization of the world economy has led to increased demands for international shipping. As a result of this increased demand, more and more cargo companies are placing orders for “jumbo” container ships with capacities of over 14,800 TEU (1 TEU or “Twenty-Foot Equivalent Unit”=1445 ft3=the volume equal to that occupied by a 20′×8½′×8½′ container) (J. Svendsen and J. Tiedemann, “The Big Ships Are Coming,” web site article dated Jul. 17, 2007: http://containerinfo.co.ohost.de). While these large ships can improve the efficiency by which goods are transported, only some 20 ports worldwide can handle them, leading to additional transportation costs and loss of time due to the ensuing necessity of transshipment from a “hub port” to the cargo's ultimate destination.
Several obstacles hinder the development of additional ports capable of handling tomorrow's jumbo cargo ships. One is the lack of available coastal land for ports. Not only is the amount of coastal land suitable for port development inherently limited, but coastal land in general is valuable and desirable for development for other purposes (e.g. residential). A second obstacle is the lack of sufficiently deep water near the coast and the massive expense that additional dredging and construction of retaining walls entails. For example, between 2000 and 2005, the Kill van Kull channel (New York/New Jersey) was deepened from 35 feet to 45 feet at a cost of $360 million, and the project currently underway to dredge the channel to the 50 foot depth required for 7000-8000 TEU capacity ships will add more than $900 million to the overall cost.
There is a further fundamental obstacle to the development of new deep-water ports accessible to jumbo container ships, namely, the way in which ports are normally engineered. The basic design of seaports has remained essentially unchanged since the time of the Roman Empire: a breakwater is constructed to provide a harbor (i.e. area of calm water), and the port constructed within that harbor. While this design has been useful for literally two millennia, it suffers from three weaknesses that limit its usefulness to contemporary port design: (1) construction of the breakwater adds significantly to the cost of the seaport (one-third of the total)—and the cost of the breakwater increases as the square of its depth; (2) the need for constant dredging on the landward side of the breakwater adds additional expense to the maintenance of the port; (3) the wide slope of the breakwater prevents mooring of ships in close proximity to it, wasting the deepest and hence most useful part of the harbor.
In the face of these obstacles, it is of vital importance that new ways of thinking about seaport design be found. Such new approaches are still lacking, however. In U.S. Pat. Nos. 5,803,659 and 6,017,167, Chattey disclosed a method of using modular caissons for seaport construction or expansion. While this invention has the cost advantages brought about by the modularity and portability of the caissons used, the port itself remains tied to land, and hence does not remove the need for the expensive dredging operations described above in cases where the water is not sufficiently deep.
Others have disclosed various means of constructing modular underwater breakwaters (e.g. the inventions disclosed in U.S. Pat. Nos. 1,816,095; 3,844,125; 4,502,816; 4,978,247; and 5,393,169), but these breakwaters are generally designed for prevention of beach erosion rather than for use in a port. Even those modular units intended for use in construction of harbor breakwaters (e.g. those disclosed in U.S. Pat. Nos. 3,614,866; 4,347,017; and 5,620,280), while reducing costs of harbor construction, envision construction of a breakwater and the piers as separate entities.
U.S. Pat. No. 6,234,714 discloses a pier with a nominally integrated breakwater. As with the above-referenced patents, however, the breakwater and pier are in fact independent structures, in which the breakwater comprises a mound of sand, gravel, rocks, and/or rubble piled up against the seaward side of the pier, upon which a plurality of caisson-like structures are placed. Thus, this design also suffers from the problems that the breakwater cannot be constructed without extensive dredging operations and that the breakwater and the pier are not a single modular structure.
Thus, there remains a need for a new paradigm for deep-water port design and construction. In order to solve the problems discussed above, what is needed is a deep-water port or an artificial island in which the breakwater is integrated into the structure itself, eliminating the costs of a dedicated breakwater construction and maintenance; in which the structure itself can be constructed in deep water without the need for additional dredging; and in which the port can be built as an independent structure not needing any direct connection to dry land, eliminating the need for free coastal land as a prerequisite for port construction or expansion. The present invention is designed to meet these long-felt needs.